Resistance-box



Patented Apr. 5, 1921.

III] I] I] F. W. MAGIN.

RESISTANCE BOX.

APPLICATION FILED IuIIIz 9,1920.

' UNITED -STATES PATENT OFFICE- TBOLLEB COMPANY, OMILWAUXEE, WISCONSIN,

A conronArIoN or WISCONSIN.

RESISTANCE-BOX.

T o `all 'whom it may concern.

Be it known that I, FRANCIS W. MAGIE, a citizen .of the United States, residing 'at A Specication of Letters Patent.

`Application led J'une 9, 1920. Serial No. 387,696.

"Patented npr. 5, 1921.

v In the present instance it isthe end walls 8, 8 whlch are ventilated and they consist of sheet metal havingaplurality of slots 10, 10

Milwaukee, in the county of Milwaukee and\\ which are approxlmately louver slots. The

State of Wisconsin, have invented a certain new and useful Improvement in Resistance- Boxes, of which the following is a speci-- My invention -relates to resistance boxes, more particularly for motor start1ng purposes, and in some respects 1t may be regarded as an improvement over the form shown in my prior Patent No. 1,076,231, granted to me March 21, 1916. Thegeneral purpose of the present invention, as 1n the previous case, is to provide a construction which will accomplish ventilation and prevent flames from issuing from the box in case of a blow-out of the resistance coils or other inclosed parts. In the patented case, a wire screen of ne mesh is employed, but this has certain disadvantages, among them being that the screen is more or less susceptible to damage and deterioration and the structure requires considerable time for production and assembly. The' objects of the present invention are to effectually prevent the issue of flames and at the sametime accomplish the result by means which are rugged,v durable, are sightly in appearance, and are simple and inexpensive to manufacture.

I accomplish my objects bythe mechanism illustrated in the accompanying drawing in whichj Figure 1 is a perspective view of an apparatus embodying my invention, a portion of the box being broken away to reveal the parts within;

Fig. 2 is a vertical section of one of the ventilated ends, this section taken onthe line 2 2 of Fig. 1;

Fig. 3 is a plan section taken on the line 3 3 of Fig. 1.

Like numerals denote like parts throughout the several views.

The construction of the resistance, coils and switching elements is not of material importance and it will be sufficient for the present purpose to say that the box or case' 1 contains resistance coils 2 of any suitable type, these coils being associated with respective contacts 3 adapted to be engaged by the shoe or contactor 4 of the controller arm 5, pivotally mounted upon the stud 6.

gain the same kind of effect asis obtainedl Y. 1n a miners lamp-that is, the opening is so restricted that the iiamlng gases in attempt- Ing to pass through, will be-chilled below the pomt whlch would enable them to ignite ,gases or objects outside of the box. These slots are formed in considerable number as indicated in theV drawings,the result being that the aggregate area of the openings is suiiicient't'o give ample ventilation and yet at v no slot can the. flame be projected to the outside.

In the developed form of invention, the hoods of the slots nea'r the bottom of the box are below the slots, so that the gases will be deflected upward; and the hoods of the slots near the top of the box are above the slots, so that the gases will be deflected downward. This creates a baffling effect for, generally in the case of a blowout, the bulk of the flame will be produced more or less at the center of the box and the flames will tend to radiate outward in all directions. If the upper slot hoods projected upward and the lower hoods projected downward, they would. be more or less in line with the lines It will be evident to those skilled in the f within :to a ignition. l 2."A` resistance box having sheet metal, 'V walls having :quasi louver slotsgformed in o them, the edges of the slots closely approach# Ha -thus described my invention what I cai ing each other forchillinghot gases attempting to issue;

3. A" resistance :box gaviggshj mmside walls and slots substantauy--lin the Y foruiof louver slots, but hawthe 'of V1 ;he'slots' close together for chilling gases attempting to 1ssue,the hoods of the slots being 'arranged approximately at right' angles to lines the box.,`

4.' A lsheet'nietai resistance box vhaving ex,

tremely narrowislots ,in the side walls for. Av entilatiom the' formation being analogous ,to louverkslots andthe hoods of the slots.

rojectingoutward and upward from the ower portlon ofthe box, and` outward and ownward from the upper portion of the ox.`

scribed my name.

jj In witness vir-hereof, VI hereunto sub-` 4Film1-tors w. MAGIK@ l 2o radiating from thecenter of x Y 

